Cavey
No need to liquid cool the GPUs. I have that haf x case with 2 x 580GTXs and have had no problems. What I would do, is get the extra top fan. You can see in the picture above, there are two top fan locations. It only comes with one. Also get a CPU closed circuit liquid cooling system. I use the corsair H70, with the fans in a push/pull setup (this means having a fan either side of the radiator. The outside pushing air against the radiator, and the inside fan pulling it away from the rad into the case), and it works like a charm. So have the front, side, and rear fans pulling air in, and the 2 tops fans pushing it out of the case. Remember heat rises, so this is the most efficient set up.
NOTE:- If you want to use RAID array, Home Premuim only gives basic raid, you need Pro or above to get all the flavours. Naturally hardware raid is better.
Do I need to us more cooling than the stock intel setup if I am not going to overclock? A buddy of mine is trying to sell me on the Cool Master V8 air cooler but I am concerned about conflict with the ram heat exchangers and the size of it and a conflict with the fans.